Giant Photogalvanic Effect-Induced Terahertz Wave Emission in Wafer-Scale Type-II Dirac Semimetal PtTe.

Terahertz (THz) emission arising from the second-order nonlinear photocurrent effects in two-dimensional quantum materials has attracted significant attention due to its high efficiency and ease of polarization manipulation. However, in centrosymmetric quantum materials, the terahertz emission is typically suppressed, caused by the directional symmetry of the photocurrent generated under femtosecond laser excitation. In this work, we report that wafer-scale type-II Dirac semimetal PtTe with lattice centrosymmetry exhibits remarkably high THz emission efficiency (2 orders of magnitude greater than that of a ZnTe nonlinear crystal with equivalent thickness) and pronounced polarization sensitivity at room temperature.

Robust ferromagnetism in wafer-scale FeGaTe above room-temperature.

The discovery of ferromagnetism in van der Waals (vdW) materials has enriched the understanding of two-dimensional (2D) magnetic orders and opened new avenues for fundamental physics research and next generation spintronics. However, achieving ferromagnetic order at room temperature, along with strong perpendicular magnetic anisotropy, remains a significant challenge. In this work, we report wafer-scale growth of vdW ferromagnet FeGaTe using molecular beam epitaxy.